Peel off the leaves as much as you can.
Cut off the stem at the bottom with the remaining leaves.
Place it with the stem below, and cut the head of the cauliflower in half.
Take a sharp knife and cut a 1-inch slice from both halves. (If you have a large cauliflower head, you may be able to cut TWO 1-inch thick slices from both halves.)
In a large stockpot, boil water with a pinch of salt on the stovetop.
Use tongs to a slotted turner to gently place the slices in the hot water.
Cover it with a lid and cook them for 5 minutes. Use medium heat to keep it simmering.
When the time is up, place them on a plate to let them cool.
In a small bowl, mix all spices for the dry rub: onion powder, mustard powder, smoked paprika powder, black paper, and salt.
Place the pre-cooked cauliflower steaks on a plate or cutting board.
Sprinkle the spice mix on both sides. Gently pat it with your fingers to make it stick.
Preheat a cast-iron skillet over medium heat and add butter.
Add cauliflower steaks, garlic cloves, and fresh rosemary twigs when the butter melts.
Fry them for 5 minutes on each side. The stem part takes the longest to soften. You can test it with the tip of the knife. In the end, the steaks should be crunchy, not too soft, so you can actually bite into them.
